Resin manufacture



Patented Jan. 12, 1943 RESIN MANUFACTURE Robert W. Martin, Savannah, Ga., assignor to Hercules Powder Company, Wilmington, Del., a corporation of Delaware No Drawing. Original application March 30,

1939, Serial No. 264,971. Divided and this application February 25, 1942, Serial No. 432,250

'7 Claims.

This invention relates to a method of producing a resin and more particularly to a method of producing from resinous wood a resin characterized by substantial insolubility in light petroleum hydrocarbons.

It has been the practice heretofore to treat resinous wood such as, for example, pine chips in order toextract therefrom rosin and various volatile terpenes such as turpentine and pine oil. Gasoline, for example, has been widely used in the extraction of rosin from pine wood and the total resinous matter so extracted is commonly known in the art as FF rosin. However, a solvent which comprises a coal tar hydrocarbon such as, for example, benzene, toluene, xylene, etc., has the property of extracting from pine wood, e. g., wood of the long leaf pine desirably in suitable form such as chips, resinous material not extracted from such wood by the use of gasoline or other light petroleum hydrocarbons, Solvents of the coal tar hydrocarbon type will, therefore, extract from pine Wood a larger quantity of resinous material.

It has been the practice heretofore to take the crude extract, obtained from extracting pine wood with a solvent of the coal tar hydrocarbon type, such as benzene and toluene, remove the solvent and volatile terpene oils by suitable means, thus recovering a solid resinous residue consisting principally of FF rosin and a resinous substance other than rosin. Heretofore this resinous residue has been separated by means of a pair of selective solvents, such as, for example, gasoline and furfural, although many other pairs of solvents are also known which will effect this separation. When the gasoline-furfural combination is used, rosin dissolves in the gasoline and the resinous substance other than rosin, dissolves in the furfural, since this substance is substantially insoluble in petroleum type hydrocarbons. Evaporation cf the furfural then leaves this resinous substance as a solid mass.

It is an object of this invention to provide a method whereby a separation of the resinous components of pine wood can be made in a simpler manner than heretofore done, directly obtaining thereby the resinous component which is substantially insoluble inlight petroleum hydrocarbons.

It is also an object to provide a method whereby the resinous component substantially insoluble in gasoline may be directly obtained in a pulverulent, free-flowing form. The resin in this form, is desirable for many purposes. By prior art methods it has been necessary to chill the solid resin, obtained as before shown, and then pulverize it to obtain it in a pulverulent form. This is an additional step and adds to the cost of the resin. Other objects and advantages of the invention will be apparent during the course of the following description.

The objects of my invention are accomplished by treating pine wood with a solvent which is capable of dissolving the normally solid resinous materials and terpene oils present in said wood, separating the extract so obtained from the wood, diluting this extract with a suflicient quantity of a substantially saturated paraffin hydrocarbon to precipitate that portion of the original extract which is substantially insoluble in solvents of this type, separating the residue so obtained from the remainder of the solution and drying this residue. The solution containing the extraction and precipitating solvents as well as the terpene oils and rosin may be suitably treated for the recovery of all the components. The extraction and precipitating solvents may be reused in the process.

The temperatures used in diluting, for example, a coal tar hydrocarbon extract of pine wood, with a substantially saturated paraffin hydrocarbon may vary over quite a range and the form of the precipitate will depend chiefly on the temperature used. If the form of the precipitate is of no particular moment, relatively high temperatures may be used but for ease of separation of the precipitate and in order to obtain a residue which, when dried, is in a pulverulent, freeflowing form, I have found that a temperature not over about 20 C. is desirable.

While I will now describe my invention particularly by reference to the preparation of a pulverulent, free-flowing product, it will be understood that the process as described is broadly applicable to the treatment of a solvent extract of pine wood containing the normally solid resinous materials and terpene oils to obtain directly from this solution a resin substantially insoluble in light petroleum hydrocarbons.

In proceeding in accordance with my invention, pine wood, preferably that from the southern long leaf pine in suitable form such as, for example, chips, may be extracted with a solvent for the FF rosin, turpentine and pine oil contained in the chips and which is likewise a solvent for the other complex substances contained in the wood chips Such a solvent may be, for example, a coal tar hydrocarbon such as, benzene, toluene, xylene, etc., and the extraction may be accomplished by flooding pine chips with the solvent with or without the use of heat. After the extraction of the chips has been sufiicient, the coal tar hydrocarbon solution of the matter extracted may be withdrawn from the wood chips.

To recover a pulverulent, free-flowing resin substantially insoluble in light petroleum hydrocarbons from the solution extract obtained from the pine chips as shown above, I may proceed in the following manner:

I may take the crude liquor obtained from the extraction of pine chips and dilute this crude liquor a substantially saturated, parafiin hydrocarbon at a temperature not higher than about 20 C. thereby precipitating an insoluble fraction in the form of a powdery precipitate. This precipitate may be readily and easily filtered from the solution and, after drying, it will be in the form of a pulverulent, free-flowing resinous substance substantially insoluble in light petroleum hydrocarbons. rial may be carried out in any number of devices such as for example, a rotary kiln drier, a tunnel drier or a vacuum drier.

The filtrate may be subjected. to distillation, yielding a distillate containing pine oil, turpentine, and the particular solvents used in the process and the residue remaining will be rosin having properties comparable to those of present crude pale rosin. If the solvents used in my process are so chosen that there is a relatively wide separation in boiling points, not only between themselves but between them and the turpentine and pine oil, fractional distillation will yield all of the components in quite pure form. The solvents used in this process and so recovered, may then be used for the treatment of successive crude liquors.

The amount of substantially saturated paraffin hydrocarbon I may use in accordance with my invention will depend upon the particular paraffin hydrocarbon used as well as the solvent initially used in extracting the pine wood. The amount used will vary in each particular case and will be so chosen as to produce a finely divided precipitate, which, after drying, will yield a pulverulent, free-flowing product.

Among the substantially saturated paraflin hydrocarbons which I may use in accordance with my invention are butane, propane, pentane, hexane or various mixtures of these as well as: low boiling petroleum distillates and petroleum ether substantially free from aromatic compounds. It will be understood, of course, that when using hydrocarbons which are normally gaseous, it will be necessary to use temperatures sufliciently low or pressures sufiiciently high to have these hydrocarbons in the liquid state.

Among the solvents which I may use for extracting the pine wood are methyl and ethyl alcohol, acetone, ethyl acetate and coal tar hydrocarbons such as, for example, benzene, toluene and xylene. Of these solvents I prefer using a coal tar hydrocarbon, especially benzene or toluene.

Having now shown the general mode of procedure, I will proceed to a more detailed description thereof by reference to the following examples.

Example 1 Four hundred grams (400) of pentane cooled to 16 C. and 400 grams of a benzene extract of pine wood cooled to C. were mixed, whereupon a fiocculent, granular precipitate was formed. The precipitate was filtered off and Drying of the precipitated matedried giving a yield of 19.4% of a pulverulent, free-flowing resin characterized by substantial insolubility in light petroleum hydrocarbons.

Example 2 The same materials and the same quantity thereof as in Example 1 were used but instead of cooling, as before, both portions were cooled to +4 to +5 C. before mixing; a fiocculent, granular precipitate was again obtained which was easily filtered off, and after drying, gave a 13% yield of a pulverulent, free-flowing resin substantially insoluble in light petroleum hydrocarbons.

Example 3 Five hundred grams (500) of pentane were added to 500 grams of a benzene extract of pine Wood at a temperature of 30 C., whereupon a fiocculent, yellow precipitate was formed. The precipitate was filtered off and dried, giving a yield of 12%. The resin so obtained is characterized by being substantially insoluble in light petroleum hydrocarbons but is not quite free-flowing as in the previous examples where a lower temperature was used. When the filtrate is evaporated, an 88% yield of rosin is obtained.

It will be understood that the details and examples given hereinbefore are illustrative only and in no way limiting on my invention as broad- 1y described hereinbefore and in the appended claims.

This application forms a division of my application, Serial No. 264,971, filed March 30, 1939.

What I claim and desire to protect by Letters Patent is:

1. A method of directly producing a resin which is substantially insoluble in light petroleum hydrocarbons which includes extracting pine wood with an organic solvent which dissolves the normally solid resinous materials and terpene oils present in said wood, separating the extract so obtained from the wood, diluting said solvent extract with a suificient quantity of propane to precipitate that portion of the resinous materials which is substantially insoluble in propane, separating said insoluble portion from the solution and drying the residue.

2. A method of directly producing a resin which is substantially insoluble in light petroleum hydrocarbons which includes extracting pine wood with a coal tar hydrocarbon which dissolves the normally solid resinous materials and terpene oils present in said wood, separating the extract so obtained from the wood, diluting said coal tar hydrocarbon extract with propane in an amount suificient to precipitate that portion of the resinous materials which is substantially insoluble in propane, separating said insoluble portion from the solution and drying the residue.

3. A method of directly producing a resin which is substantially insoluble in light petroleum hydrocarbons which includes extracting pine wood with benzene, said extract containing the normally solid resinous materials and terpene oils present in said Wood, diluting said benzene extract with propane in an amount sufficient to precipitate that portion of the resinous materials from the benzene extract which is substantially insoluble in propane, separating said insoluble portion from the solution and drying the residue. i

4. A method of directly producing a resin which is substantially insoluble in light petroleum hydrocarbons which includes extracting pine wood with toluene, said extract containing the normally solid resinous materials and terpene oils present in said wood, diluting said toluene extract with propane in an amount sufficient to precipitate that portion of the resinous materials from the toluene extract which is substantially insoluble in propane, separating said insoluble portion from the solution and drying the residue.

5. A method of directly producing a pulverulent, free-flowing resin which is substantially insoluble in light petroleum hydrocarbons which includes extracting pine wood with a coal tar hydrocarbon which dissolves the normally solid resinous materials and terpene oils present in said wood, separating the coal tar hydrocarbon extract from the wood, adding to said extract at a temperature not above about 20 C. a sufiicient quantity of propane to precipitate from said extract an insoluble residue in finely divided form, separating this insoluble residue from the solution and drying said residue to obtain a pulverulent, free-flowing resin having the aforesaid characteristic.

6. A method of directly producing a pulverulent, free-fiowing resin which is substantially insoluble in light petroleum hydrocarbons which includes extracting pine wood with benzene which dissolves the normally solid resinous materials and terpene oils present in said wood, separating the benzene extract from the wood and adding to said extract at a temperature not above about 20 C. a sufiicient quantity of propane to precipitate from said extract an insoluble residue in finely divided form, separating this insoluble residue from the solution and drying said residue to obtain a pulverulent, free-flowing resin having the aforesaid characteristic.

7. A method of directly producing a pulverulent, free-flowing resin which is substantially insoluble in light petroleum hydrocarbons which includes extracting pine wood with toluene which dissolves the normally solid resinous material and terpene oils present in said wood, separating the toluene extract from the wood and adding to said extract at a temperature not above about 20 C. a sufficient quantity of propane to precipitate from said extract an insoluble residue in finely divided form, separating this insoluble residue from the solution and drying said residue to obtain a pulverulent, free-flowing resin having the aforesaid characteristic.

ROBERT W. MARTIN. 

